We have recently succeeded in isolating the replicative origin of the Escherichia coli chromosome. The complex is composed of the DNA at and near the origin, and various proteins. We call this complex OC, for "origin complex". We will attempt further characterization of the OC particles. specifically, we will purify them with regard to protein content, and attempt to characterize the intrinsic proteins of these particles. Preliminary results have shown that partially purified DNA from OC binds to outer membrane, while other DNA does not. We will use a filter-binding assay to determine further the specificity and other properties of this interaction.